Fuel for compression ignition engines



- Patented Nov. 19, 1940 UNITED STATES R-ATENT OFFICE FUEL FOR COMPRESSION IGNITION ENGINES David Lipkin, Berkeley, Calif., assignor to The Atlantic Refining Company, Philadelphia, Pa, a corporation of Pennsylvania No Drawing.

9 Claims.

in the ignition temperature of the fuel oil and/or a lowering of the compression ratio of the engine. 15 A more specific object relates to compression ignition fuels comprising straight-chain aliphatic ethers of suitable volatility, or fuels containing quantities of such ethers suflicient to effect the desired improvement. M In accordance with the present invention, it has been found that when one or more of the straightchain aliphatic ethers are added to a fuel 011 there is obtained a reduction in the delay period between injection and ignition of the fuel oil. This phenomenon is accomplished by a lowering of the ignition temperature of the fuel oil and/ or a lowering of the compression ratio in the compression engine required to ignite the fuel.

The ethers to be employed in accordance with this invention have, in general, a boiling point not less than substantially 100 C. and are substantially miscible with hydrocarbon fuel oils. Such ethers may contain either simple or mixed functions, 1. e., the aliphatic radicals may be similar or dissimilar. The preferred compounds are the monoand poly-ethers having straight-chain alkyl or substituted alkyl groups attached directly to the ether oxygen. Among the ethers which may be employed, per se, as fuels, or as ignition accelerators for fuel oils, may be mentioned the simple ethers such as n-butyl ether, n-amyl ether, n-hexyl ether, cetyl ether, lauryl ether, oleyl ether, stearyl ether and the like. The mixed ethers may be exemplified by n-butyl amyl ether, n-amyl hexyl ether, cetyl lauryl ether, oleyl stearyl ether and the like. The aliphatic straightchain ethers which may suitably be employed also include the monoor dimethyl ethers of 50 ethylene glycol, the monoor diethyl ethers of ethylene glycol, the butyl ethers of ethylene glycol, the ethyl ethers of diethylene glycol, the butyl ethers of diethylene glycol and the like. While it is preferable to employ ethers containing only straight-chain aliphatic groups, other ethers hav- Application October 20, 1938, Serial No. 106,535

ing a slightly branched long chain, e. g., diisoundecyl ether, have been found suitable.

The following examples are illustrative of the results which may be obtained in accordance with the present invention. The cetane number of the fuel is employed herein as an index of the quality of the fuel, and an improvement in the fuel is expressed by an increase in the cetane number. The base fuel oil employed in the examples had an A, P. I. gravity of 233 and a. distillation range of from 398 F. to 620 F..

Celgnition accelerator (vol. percent) iiarne o.

The quantity of ether employed will depend upon the degree of improvement required, and may vary from about by volume of the fuel to 50% or 100%. The ethers of the present invention are characterized in having boiling points or boiling ranges above about 100 C. and preferably within the range of from about 100 C. to about 300 C. Low boiling ethers such as methyl andethyl ether are too volatile to be suitable as addition agents for compression ignition fuels, and such highly volatile ethers are not contemplated as within the scope of this invention.

Among the advantages which accrue from the .use of straight-chain ethers as ignition accelerators in compression ignition fuels may be mentioned:

(1) Elimination of knocking and rough-running by decreasing the ignition lag.

(2) Easier starting due to the reduced spontaneous ignition temperatures of the blended fuel.

(3) Possibility of using inferior grade of fuel oil. By the addition of the accelerator, low grade fuels which at present are unsuitable for use in compression ignition engines, may be rendered equal or superior to high grade unblended fuels.

The above description and examples are to be taken as illustrative only and not as limiting the scope of the invention. Any modification or variation therefrom which conforms to the spirit of the invention is intended to be included within the scope of the claims.

In the appended claims the term gasoline boiling range refers to a temperature range of the order'of about 90 F. to 390 F.

What I claim is:

1. A motor fuel for high speed Diesel engines having a boiling range substantially above that of gasoline, which comprises fuel oil and at least 5% by volume of a straight-chain aliphatic ether boiling within the range of from about 100 C. to about 300 C.

- 2. A motor fuel for high speed Diesel engines having a boiling range substantially above that of gasoline, which comprises fuel oil and at least 5% by. volume of an ether boiling within the range of from about 100 C. to about 300 C., said ether containing at least one straight-chain aliphatic group attached to the ether oxygen atom.

3. A motor fuel for high speed Diesel engines having a boiling range substantially above that of gasoline, which comprises fuel oil and atleast 5% by volume of an ether boiling within the range of from about 100 C. to about 300 C. and having the formula R-O-R', wherein R and R are straight-chain alkyl groups.

4. A motor fuel for high speed Diesel engines having a boiling range substantially above that of gasoline, which comprises fuel oil and at least 5% by volume of n-butyl ether.

5. A motor fuel for highspeed Diesel engines having a boiling range substantially above that of gasoline, which comprises fuel oil and at least 5% by volume of n-amyl ether.

6. A motor fuel for high speed Diesel engines 6 having a boiling range substantially above that of gasoline, which comprises fuel oil and at least 5 {7; by volume of mono-butyl ether of diethylene g co 7. Diesel motor fuel oil of improved cetane 10 number comprising petroleum oil boiling above the gasoline range and containing at least 5% of a dialkyl ether selected from the group consisting of di normal butyl ether and di normal amyl ether. v 15 8. Diesel motor fuel oil of improved cetane number comprising petroleum oil boiling above the gasoline range and containing at least 5% of di normal butyl ether.

9. Diesel motor fuel oil of improved cetane 20 number comprising petroleum oil boiling above the gasoline range and containing at least 5% of di normal amyl ether.

DAVID LIPKIN. 

